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Definitions |
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Are Clara cells ciliated and mucous-secreting?
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No
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What is Waldeyer's ring?
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The abundent mucosa-associated lymphoid tissue located deep to the nasopharynx epithelium
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T/F: The lung has the richest capillary network of any organ in the body and the largest blood flow.
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True
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What are causes of hypoventilation?
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Airway Obstruction
Restiction of chest wall or lung parenchyma
Respiratory depression by drugs, alcohol, or disease
Spinal Cord injury affecting respiratory centers
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What is the Respiratory Quotient?
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Carbon Dioxide Production/Oxygen Consumption
Averages 0.8 since oxygen consumption is more than CO2 production.
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What is the partial pressure of water vapor in humidified inspired air?
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47mmHg
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What is the Shunt Equation?
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Shunt Fraction = QS/QT
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What is the average alveolar oxygen partial pressure?
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100 mm Hg
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What are the four essential elements involved in the mechanism of ventilation?
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Thoracic skeleton
Intercostal muscles
Diaphragm
Elastic connective tissue within the lung
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The respiratory portion of the respiratory system is composed of what?
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respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli
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What are the last 7 generations of airways called?
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Respiratory Zone
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Gas exchange of both O2 and CO2 occurs through the passive force of __________.
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diffusion
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What is the normal (A-a) DO2 difference on room air?
On 100 Saturation O2?
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20 mmHg
100 mmHg
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What is myoglobin?
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Another heme monomer that does not demonstrate cooperativity with regard to oxygen affinity.
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What is erythropoietin?
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A small peptide formed in the kidney in response to stimuli related to the oxygen carrying capacity of blood; the hormone stimulates red blood cell formation
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What factors affect diffusion according to Graham's Law?
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Diffusion is inversely proportional to the square root of the molecular weight of the gas and the thickness of the barrier
Diffusion is proportional to the surface area and the solubility of the gas in water
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What is the equation for the inspired partial pressure of oxygen?
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PiO2 = (Pb-47)*FiO2
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What are the five listed possible causes of hypoxemia?
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Altitude, alveolar hypoventilation, diffusion abnormalities, ventilation-perfusion imbalance, and intrapulmonary shunt
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Describe Type I pneumocytes
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Represent 40% of the alveolar cell population, but for 90% of the alveolar lining
They are FLAT
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What are some ways that perfusion is decreased in the lungs?
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Pulmonary Emboli
Emphysema
Pulmonary Fibrosis
Adult Respiratory Distress Syndrome
Heart Failure, Hypotension and Hypo-Perfusion
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1. What is PaCO2 during hypoventilation?
2. Hyperventilation?
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1. >45 mmHg
2. <35 mmHg
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What is the average blood hemoglobin concentration?
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15 g Hb/100ml blood
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What is the Hamburger shift?
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The movement of the bicarbonate anion is coupled to a chloride-bicarbonate cotransport system which moves chloride ion into the erythrocyte in exchange for the bicarbonate
Takes place within tissue
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Bronchioles lack ____________ but have an increased amount of ____________ and ___________.
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Bronchioles lack cartilage plates but have an increased amount of elastic fibers and smooth muscle cells.
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What are two ways that alveolar ventilation can be decreased?
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Increased airway resistance and decreased lung compliance
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What are the two stages of Respiration?
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1. Gas Exchange
2. Cellular Respiration
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What is Dalton's Law?
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Total Pressure is the sum of the partial pressures of the individual gases in the atmosphere.
Partial pressures of gases are found by the fraction of each gas in the mixture
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What is the value of O2 for arterial hypoxemia?
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PaO2 <70 mmHg
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What is the value of O2 for Respiratory Failure?
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PaO2 < 50 mmHg
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Where is erythropoeitin formed?
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Formed in the kidneys in response to stimuli related to the oxygen carrying capacity of blood.
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What two factors can affect the concentration gradient of oxygen from atmosphere to blood?
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1. Total Barometric Pressure
2. Partial Pressure of oxygen will vary as a function of its percentage composition (humid vs. dry air)
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Diffusion abnormalities are caused by diseases that reduce what?
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The cross sectional area of the alveolar-capillary bed
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What are the epithelium types of the nasal vestibule?
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External surface - keratinized stratified squamous epithelium
Internal surface - non-keratinized stratified squamous epithelium
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What is the relationship between level of alveolar ventilation and PACO2?
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As alveolar ventilation increases, the level of PACO2 decreases.
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What is Respiratory Dead Space?
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This is any portion of lungs that receives adequate ventilation, but does not receive any blood flow (perfusion).
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1. What is the normal tidal volume?
2. What is the normal minute volume?
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1. 500 ml
2. (500)(12 breaths/minute) = 6L
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What are some of the factors that affect affinity of Hb for O2?
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Temperature - higher temperature shifts curve right
pH - lower pH shifts curve to the right
2,3 DPG - more shifts curve to right
Carbon Dioxide - more shifts curve towards right
Genetics
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In what ways does carbon dioxide travel in the blood?
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Dissolved - represents a small amount of the total gas transported
Carbamino compounds - formed by the combination of CO2 with amino acids and plasma proteins (hemoglobin)
Bicarbonate - transports the greatest amount of CO2; accomplished with carbonic anhydrase
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What is the purpose of determining (A-a) DO2?
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This calculation is used to determine the presence and severity of a gas exchange abnormality
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What is the numerical definition of arterial hypoxemia and respiratory failure?
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Arterial hypoxemia is defined as a PaO2 Respiratory failure is defined as a PaO2
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What are the 2 functions of the larynx?
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Protection of the airway and vocalization
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T/F: Inspired gas contains a large amount of Carbon Dioxide.
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False. Inspired gas contains no Carbon Dioxide. All CO2 comes from aveolar gas.
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1. What is Functional Residual Capacity?
2. What is the normal value?
3. Can it be measured with a spirometer?
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1. Volume of gas remaining in lung following a normal quiet expiration.
2. 1.8 - 2.4 L
3. No
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Where is the appropriate place to measure values for mixed venous blood?
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In the pulmonary artery PvO2, which ensure adequate mixing.
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What are the components of the Diffusion Capacity?
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1. molecular weight of the gas
2. solubility in water
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When do the effects of anemia become apparent?
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What patients exercise and cannot meet their metabolic requirements even after increasing blood flow to their tissues
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What is the purpose of the Fick equation? What is the equation?
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To determine the cardiac output in research and clinical medicineCO = O2 consumption / (A-V) O2 Content Difference
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What is the purpose of the conchae in the nasal cavity?
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The conchae causes airflow turbulence which facilitates contact between the air and the mucous coating covering the respiratory region
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Which equation is used to measure Dead Space?
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THe Bohr Equation measures the VD/VT ratio. In normal individuals, physiological dead space will equal anatomic dead space. In diseased individuals, physiological dead space will increase.
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1. What is Residual Volume?
2. What is the normal value?
3. Can it be measured with a spirometer?
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1. Volume of air remaining in lungs after maximal forced expiration
2. 1-1.2 L
3. No
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What is the effect of increased tissue extraction of oxygen on the A-V range?
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Since more oxygen is being extracted the range will become broader
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In what tissues is the diffusing capacity a rate limiting step?
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NOT in the lungs; in the lungs, the pressure gradient is the important factor of the alveolar gas exchange equation
Usually in tissues where the distances are much greater
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What is the average tissue, mixed venous blood, alveolar, and atmospheric CO2 partial pressures?
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tissue - 50 mm Hg
mixed venous - 46 mm Hg
alveolar - 40 mm Hg
atmospheric - 0.23 mm Hg
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What are the four cell types of the olfactory epithelium and describe them
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Basal cells - mitotically active and produce immature olfactory neurons
Differentiating (immature) olfactory neurons - arise from basal cells; proliferate during adult life; differentiate into mature olfactory neurons
Mature (bipolar) olfactory neurons - highly polarized, apical region directed toward muscosal lining and possesses 10-20 modified cilia; axon forms at its basal region; axons pass through cribiform plate of ethmoid bone to synapse on cells of the olfactory bulbs; lifespan of 30-60 days
Sustentacular (supporting) cells
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What is the equation for alveolar volume?
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VA = VT - VD
Alveolar Volume = Tidal Volume - Dead Space Volume
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1. Why is the PaO2 less than PAO2?
2. What is the normal value of difference between the two and what is the term for it?
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1. Since matching of perfusion and ventilation in the lungs is not perfect. Also due to the fact that a small amount of venous blood bypasses the pulmonary capillaries and enters into the arterial circulation without being exposed to alveoli.
2. 7-10mmHg, Alveolar-Arterial Oxygen Gradient
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What will cells do when faced with hypoxemia?
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They will extract more O2 from the blood to compensate for reduced PaO2
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What is the normal amount of delivered oxygen that is consumed by tissue? How high can it go to compensate for anemia, hypoxemia, low cardiac output, etc.?
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At rest, only about 25 to 30% of delivered oxygen is consumed by the tissues at restTissue oxygen extraction can reach 40-45% of the amount delivered to compensate for situations of low O2
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For each 500 ml of inspired air, how much does not take part in gas exchange?
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150 ml. This is referred to as anatomic dead space.
.
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1. What is Forced Expiratory Volume 1 Sec?
2. What is the normal value?
3. Can it be measured with a spirometer?
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1. Volume of air that can be expired in one second
2. FEV1/VC = >80%
3. Yes
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What is the normal level for indexed oxygen delivery?
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Between 500 and 600 ml per minute per square meter of body surface area.
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Moderate shifts to the right of the Hb curve lead to (increased/decreased) oxygen unloading in the tissues.
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increased. This is because Hb has a lower affinity for O2 as the curve shifts to the right. However, as long as alveolar PO2 is above 70, the slightly less affinity does not affect loading in lungs due to the sigmoid shape of the curve.
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